<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <div :style="style1"></div>
        <div :style="{ width:100+200+300+'px',height:height+'px',background:'skyblue' }"></div>
    </div>
    <script src="./vue.js"></script>
    <script>
        let vm = new Vue({
            el:"#app",
            data:{
                style1:{
                    width:'100px',
                    height:'100px',
                    background:'red'
                },
                height:300
            }
        })
    </script>
</body>
</html>